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DEPARTMENT OF COMMERCE 

MS, BUREAU OF FISHERIES 

HUGH M. SMITH, Commissioner 



EXPLORATIONS OF THE UNITED STATES COAST AND GEO- 
DETIC SURVEY STEAMER ^^BACHE^' IN THE WESTERN 
ATLANTIC, JANUARY-MARCH, I9I4, UNDER THE 
DIRECTION OF THE UNITED STATES 
BUREAU OF FISHERIES 

OCEANOGRAPHY 

By Henry B. Bigelow 



APPENDIX V TO THE REPORT OF THE U. S. COMMISSIONER 
OF FISHERIES FOR I9I5 




Bureau of Fisheries Document No. 833 



WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1917 






QsM- 



>y 



\D 



ADDITIONAL COPIES 

CF THIS PUBLICATION MAY BE PROCURED FROM 

THE SUPERINTENDENT OF DOCUMENTS 

GOVERNMENT PRINTING OFFICE 

"WASHINGTON, D. C. 

AT 

15 CENTS PER COPY 



MAY 26 191? 



5\ 



K 



CONTENTS. 



Introduction 5 

The Atlantic water 6 

Temperature and salinity profiles 14 

The Straits of Florida 26 

The coastwatei off Chesapeake Bay 45 

Tables 55 

Bibliography . 60 

3 



EXPLORATIONS OF THE UNITED STATES COAST AND GEODETIC SURVEY 
STEAMER *^BACHE'^ IN THE WESTERN ATLANTIC, JANUARY-MARCH, 
mi, UNDER THE DIRECTION OF THE UNITED STATES BUREAU OF 
FISHERIES,— OCEANOGRAPHY. 



By Henry B. Bigelow. 



IlfrRODUCTION. 

In connection with the oceanographic and fishery investigations 
between the Grand Banks and Cape Hatter as which have been 
prosecuted by the Bureau of Fisheries for a number of years (Bige- 
\ow, 1914a-1915), there developed an appreciation of the importance 
of studying the conditions between the southern Atlantic coast and 
the Bermudas, Bahamas, and Cuba. As the Bureau of Fisheries 
had no vessel on the Atlantic coast which was suitable for this off- 
shore work, a request for assistance and cooperation was preferred to 
the Coast and Geodetic Survey, which also was interested in certain 
phases of the investigation, particularly the physical hydrography. 

The Superintendent of the Survey promptly acquiesced in the 
suggestion and under an arrangement for an equitable division of 
expenses, the Coast and Geodetic Survey steamer Bache, under the 
command of Capt. C. C. Yates, was assigned to the duty. The in- 
vestigations were under the direction of the Bureau of Fisheries, W. W. 
Welsh, assistant in that Bureau, having immediate charge. The 
cruise lasted from January 20, 1914, to March 23 of the same year. 

The course of the Bache (see chart) led from Chesapeake Bay to the 
oceanic basin in longitude 73° 15', thence south to latitude 32° 30', 
and from that point to Bermuda. SaiUng from Bermuda on Feb- 
ruary 17, she ran 200 miles southwest, to latitude 29° 30', then west 
to a point 140 miles north of the Bahamas, and south to Nassau. 
Three sections were then run across the Straits of Florida, viz, Key 
West to Habana, Founey Rocks (Cape Florida) to Gun Cay, and 
Jupiter Inlet to the northern end of the Little Bahama Bank (Mar. 
13-21); and, finally, a line thence to connect with the Bermuda- 
Bahama hne. Serial oceanographic observations were taken at 38 
stations and surface temperatures and water samples at 19 addi- 
tional stations. The temperatures " were taken with reversing ther- 
mometers of the" latest type, with auxihary thermometers to give the 

a Temperatures are centigrade. 



6 EXPLOBATIOISrS^ WESTERN ATLANTIC^ STEAMER BACHE^ 1914. 

temperature of the detached thread of mercury at the moment of 
reading. The water samples were collected with Ekman reversing 
water bottles (Ekman, 1905b) and with the Bigelow stopcock water 
bottle (Bigeiow, 1914a), Unfortunately, the former proved unrehable 
in the strong currents in which much of the work was carried on; 
consequently a number of the water samples are untrustworthy, and 
such have been omitted from the table of salinity (p. 55). 

The limitation of the gear on the Bache made it impracticable to 
work deeper than 1,800 meters. Only occasionally were water 
samples or temperatures taken on the sounding wire at greater 
depths; but down to 1,800 meters the records are sufficiently fuU 
to afford a satisfactory survey of both temperature and salinity. 

Throughout the cruise the weather was most unfavorable. There 
was a constant succession of gales, occasionally of almost hurricane 
strength, taxing vessel and personnel to the utmost. 

The salinities were executed in the laboratories of the United 
States Bureau of Fisheries at Washington. 

THE ATLANTIC WATER. 

The Bache stations give a survey of the upper 1,800 fathoms be- 
tween Chesapeake Bay and Bermuda; from Bermuda to a point 200 
miles to the southwest ; and between the latter and the northern end 
of the Bahama Bank. (See chart.) Off Chesapeake Bay the surface 
temperature (fig. 1) rose suddenly from about 12° over the 200-meter 
contour to 21.5° 80 miles farther east. This very warm water was 
evidently only a very narrow band, for as a rule the surface water, 
as far as Bermuda, was 18.8°-19.5°. Close to Bermuda the surface 
temperature was 18°-19°; but about 200 miles farther south it rose 
to 21°, and on the line to the Bahamas it was constantly 20° or 
warmer, except between longitude 67° 30' and 71°, where cooler 
water was encountered. North of the Bahamas the surface water 
warmed to 23°; and it was even warmer, 23.6°, at the mouth of the 
Straits of Florida, off Jupiter Inlet. These observations show that 
there were four fairly distinct temperature zones, as outlined on the 
chart (fig. 1): First, the coast water off Chesapeake Bay, 15° or 
colder, which probably extends, though with constantly rising tem- 
perature, to Savannah; second, the general warm water of the An- 
tilles drift, with temperatures warrner than 20°, which swings north- 
eastward paraUel to the coast, reaching latitude about 36° in Jan- 
uary and February; third, the superheated water coming from the 
Gulf of Mexico, via the Straits of Florida, which gradually merges 
with the Atlantic water; and, fourth, a comparatively cool region 
west of Bermuda, no doubt continuous with the colder water farther 
north. AU this, of course, agrees in its main lines with the earlier 



EXPLOEATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 7 

temperature charts (Agassiz, 1888; Berghaus, 1891; Deutsche See- 
wahrte, 1882) and the correspondence with Schott's (1912) chart for 
the month of February is extremely close. Thus there is no reason 
to suppose that the surface temperatures in the winter of 1913-14 
were anything but normal. 

In the eastern haK of the region surface salinity (fig. 2) agreed very 
well with surface temperature, being lower than 36.5°/oo to the west 
and southwest of Bermuda; with the curve for 36.5°/oo nearly par- 
alleling the curve of 20° temperature here, and the curve of 36.6%o 




Fig. 1.— Surface temperature of the western Atlantic, coast of United States to Bermuda, January to 

March, 1914. 

that for 21°. Water salter than 36.5"/oo formed a very well-defined 
tongue swinging northeastward from the Bahama Bank, the curve 
for 36.4<'/oo paralleling the coast line, with water fresher than 35°/oo 
next the land off Cape Hatteras, and probably as far south as north- 
ern Florida. The 36.5%o water may be definitely classed as the 
continuation of tho Antilles current, thus agreeing with the tempera- 
ture curves; the slightly fresher water (36-36.4''/oo) west of it as largely 
Florida current water; and the stiU fresher water next the coast north 
of Florida as coast water. 



8 EXPLOEATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

Schott's (1902) chart of average surface salinity for the year shows 
the same northward tongue of 36.5°/oo or Antilles water, as is to be 
seen on the Bache chart (fig. 2); but most of the critical area is 
blank for want of data. The records since collected by the inter- 
national committee for the exploration of the sea (1909, 1910, 
1911) add very little to our knowledge of the region in question, 
those for this general part of the Atlantic being chiefly limited to a 
line from the neighborhood of Bermuda to Jamaica. In short, pre- 
vious salinity records, at least by modern methods, are so scanty for 



CAPE HATTER 



BERMUDA 




'BAHAin^S 

1 



Fig. 2.— Surface salinity of the -western Atlantic, coast of United States to Bermuda, January to March, 

1914. 

the region crossed by the Bache that it is impossible to state whether 
the conditions which she encountered there are characteristic of the 
winter season. 

Typical examples of the serial temfperatures and salinities taken by 
the Bache between the continental slope and Bermuda, and between 
Bermuda and the Bahama Bank, which are given in full in the tables 
(p. 55), are represented graphically in the accompanying sections 
(fig. 3-10). The temperatures aU agree in showing a general cool- 
ing from 19°-22° on the surface to about 4° at 1,800 meters. The 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 9 

curves southwest of Bermuda are all approximately parallel, though 
with shght variations in the middepths, and especially near the 
surface. Between Bermuda and the Chesapeake (fig. 3) there are 
great variations in temperature station to station, between 700 and 
1,400 meters, though the temperature was comparatively uniform at 
1,800 meters and between 700 meters and the surface. This was 
also the case, though to less degree, north and northeast of the Ba- 
hamas (fig. 6). On the whole the middepths were warmest 



X 



Temperature, Centigrade 

Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 
180Q 

Fig. 3. — Temperature sections between the continental slope off Chesapeake Bay and Bermuda, stations 
10163, 10171, 10177; and Challenger station 37, 40 miles west of Bermuda, April 24, 1878 ( ). 

west of Bermuda (station 10177), coldest north of the Bahamas 
(stations 10210-10212) and in the northeast Providence Channel 
(station 10196), if we omit for the moment the very much colder 
water over the continental slope. In the upper layers, between, say, 
300 meters and the surface, the Antilles water was warmest, this rela- 
tionship of the various stations to one another being more clearly 
revealed by the profiles (fig. 11, 12, 15) and charts of temperature 
at different levels (fig. 17, 18, 20). 



4 


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10 EXPLOEATlOlSrS, WEST'ERlSr ATLANTIC, STEAMEB BACHE, 1914. 

The course of the Challenger in 1873 crossed that of the Bache at 
Bermuda, allowing a direct comparison of the vertical distribution 
of temperatures for 1873 (Murray, 1884) and 1914 in that neighbor- 
hood. The temperature series taken by the Challenger about 260 
miles south of Bermuda in March of that year {Challenger station 29), 



Temperature, Centigrade 

fi A CO e 

Meter 

100 

200 

300 

400 

500 

600 

700 

800. 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 
1800 

Fig. 4.— Temperature sections on a line miming 200 miles southwest from Bermuda; stations 10179, 10181, 
10183; and Challenger station 37 ( ) . 

agrees very closely with the serial at Bache station 10185, except near 
the surface, as shown by the following table : 



3 4 


5 


° 6 


7 


8 


S 


1 10° 1 


12 13 1 


4 15° 16 17 18 


19 2 


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Depth in meters. 


Bache 
station 
10185. 


Bache 
station 
10212. 


Challen- 
ger sta- 
tion 29. 


Depth in meters. 


Bache 
station 
10185. 


Bache 
station 
10212. 


Challen- 
ger sta- 
tion 29. 





° C. 
19.8 
19.55 
18.6 
17.3 
16.4 
15.5 
14.4 
11.7 
9.07 
8.2 


° C. 
20.75 
20.5 
19.2 
17.77 
10 

14.62 
12.8 
10.8 

9 

7 


° c. 

22.2 
20.3 
18.2 
17.5 
16.7 
15.5 
13.8 
11.5 

9 

7.3 


1,000 


" C. 
7.1 
6.2 
5.4 
4.8 
4.44 
4.1 
3.9 
3.8 
3.77 


" C. 
5.62 
5 

4.6 
4.4 
4.2 
4 

3.8 
3.7 
3.67 


" C. 

5.8 


100 


1,100 


4.7 


200 


1,200 


4.6 


300 


1,300 


4.5 


400 


1,400 


4.5 


500 


1,500 


4.2 


COO 


1,600 


4 


700 


1,700 


3.9 


800 


1,800 


3.9 


900 











EXPLOBATIONS, WESTEEK ATLAKTTG, STEAMER BACHE, 19U. H 

Between 200 and 800 meters, and again "below 1,200 meters, the 
greatest difference is only 0.6°, hardly more than the probable error 
of the curves from which the table is constructed. Above 200 meters 
the Challenger series is decidedly the warmer; but this difference is 
probably due to the geographic location of the stations, the tempera- 
ture of 1914 (fig. 1) suggesting that in that year also the surface 
reading would have been above 21° at the locality of the Challenger 
station. Between the 800 and the 1,200 meter levels the tempera- 
tures were from 0.6° to 1.5° lower in 1873 than in 1914; but here again 



3 4 5° 6 7 



Temperature, Centigrade 

8 9 10° 11 12 13 14 15° 16 17 18 19 20° 21 22 



\ 



Meter 

100 

200 

300 

400 

500^ 
.600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600, 
1700 
1800 

Fig. S.— Temperature sections between Bermuda and the Bahama bank; stations 10185, 10187, 10191. 

it may be the difference in geographic location which is responsible, 
the lower temperature of the Challenger station at this depth being an 
indication of the general and well-known upwelling of abyssal water 
toward the Equator. Indirect evidence to this effect is afforded by 
the fact that these Challenger temperatures agree almost exactly, 
below 800 meters, with Bache station 10212 on nearly the same 
latitude north of the Bahama Bank, and they do not differ from the 
latter by more than 1.4° at any depth, as illustrated in the preceding 
table (p. 10). 

































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12 EXPLOEATIONS^ WESTEEN ATLANTIC, STEAMEE BACHE, 1914. ■! 

The temperatures a few miles south of Bermuda agree very closely 
for the two years, one being slightly colder at some depths, the other 
at other depths, as illustrated by the following table, constructed 



Temperature, Centigrade 
4 5° G 7 8 9 10° 11 12 13 14 15° IB 17 18 19 20° 21 22 23 



Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 

1000 

1100 

1200 

1300 

1400 

1500 

160G 

1700 

1800 



Fig. 6.— Temperature sections in the oceanic basin east of the Bahama Bank; stations 10193, 10210, 10212; 
and in the northeast Providence channel, station 10196. (Down to 1,800 meters only.) 

from the temperature curves for Challenger station 57b, 20 miles 
southwest of Bermuda (Murray, 1884), and Bache station 10181: 





































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Depth in meters. 



0. 
100. 
200. 
300. 
400. 
500. 
600. 
700. 
800. 
900. 



Bache 
station 
10181. 



° C. 
19.37 
18.78 
18.89 
18.2 
17.13 
16.3 
15.2 
13.2 
10.7 
8.7 



Challen- 
ger sta- 
tion 576. 



° C. 
22.78 
19.7 
18.5 
17.8 
17.2 
16.6 
15.4 
13.5 
11.2 
9 



Differ- 
ence. 



° C. 
+3.41 
+ .92 

- .39 

- .6 

- .07 
+ .3 
+ .2 
+ .3 
+ .5 
+ .3 



Depth in meters. 



1,000 
1,100 
1,200 
1,.300 
1,400 
1,500 
1,600 
1,700 
1,800 



Bache 


Challen- 


station 


ger sta- 


10181. . 


tion 57b. 


° C. 


- C. 


7.38 


6.5 


6.5 


5.3 


5.7 


4.7 


5.2 


4.4 


4.88 


4.2 


4.4 


3.9 


4 


3.8 


3.9 


3.7 


3.89 


3.5 



Differ- 
ence. 



The only important difference — the warmer surface in 1873 — -is no 
doubt due to the fact that observations were taken in May, 1873, 
and in February, 1914. 



EXPLORATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 13 

Off the west slope of the Bermudas the temperature of the mid- 
depths was much higher in 1914 {Bache stations 10173-10177) than 
in 1873, though in the ahyss and above about 700 meters there was 
little difference (fig. 3) . This divergence seems to have been a local, 
not a general, phenomenon, for the two Challenger stations within 100 
miles west and northwest of Bermuda (no. 37 and 38) agree much 
more closely with Bache station 10171 (fig. 3). So far as these 
records go there seems to have been little difference in the tempera- 



.9 3 


5 . 


1 . 


2 . 


3 


4 . 


Salinity; 

5 .6 .7 .8 ; 


5^0 
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3 


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Meter tf 

100 

200 

300 
\ 400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 
1800 

FiQ. 7.— Salinity sections between the continental slope off Chesapeake Bay and Bermuda; stations 10163, 

10171, 10177. 

tures of 1873 and 1914 in this part of the Atlantic as a whole; but the 
water in the neighborhood of Bermuda was much more uniform in 
1873 than in 1914, when there was a very considerable variation of 
temperature at 800 to 1,200 meters between stations west (10177) 
and others south of the island. 

The salinity cm-ves, Hke those for temperature, all approach a 
nearly uniform value at 1,800 meters, viz, 34. 9-35^/00 ; and, like 
the temperatures, they show the greatest variations in the mid- 



14 EXPLORATIONS^ WESTERN ATLANTIC^ STEAMER BACHE, 1914. 

depths between 500 to 1,500 meters, the extreme range at 1,200 
meters being only 7°/oo (34.8-35.5°/oo)- The salinity of the mid- 
depths, hke the temperatm-e, was highest west of Bermuda, where 
water of 35.2 per cent was encomitered at . about 1,500 meters; 
lowest north and northeast of the Bahama Bank (stations 10193, 
10210, 10212) and in the northeast Providence Channel (station 
10196), where water of this sahnity was within 700-800 meters of 
the surface. So far as I can learn, no serial salinities have pre- 



Salinity; JJo 
34.9 35 .1 .2 .3 .4 .5 .6 .7 .8 



,9 36 »1 J2 .3 .4 .5 .6 .7 



Meter 

100 

200 

300 

400 

500 

600 

700 

80G 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 
1800 

Fig. 8.— Salinity sections on a line running 200 miles southwest from Bermuda; stations 10179, 10181, 10183. 

viously been taken by modern methods in the region in question, 
the Challenger records being aU open to suspicion because of unre- 
liable water bottles. 

^ TEMPERATURE AND SALINITY PROFILES. 

The profile from Chesapeake Bay to Bermuda (fig. 11) is neces- 
sarily interrupted between stations 10161 and 10163, o^dng to the 
zigzag course followed. (See chart.) On this hne water warmer than 
20° was confined to a narrow surface belt just east of the 1,800-meter 
contour on the continental slope (station 10161), with a secondary 































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EXPLOKATIOlSrS, WESTEKN ATLANTIC, STEAMER BACHE, 1914. 15 

band at station 10165; otherwise the temperature was very uniform 
east of station 10163 above 650 meters, the curve for 15° being 
ahnost horizontal at that level, to swing up to the surface near the 
land as described elsewhere (p. 47). And, again, the temperature 
was nearly uniform at 1 ,800 meters east of station 10163. But in the 
middepths there is a very pronomiced upweUing of cold water, 
revealed by the ciu-ves for 5° and 10°, in the center of the profile, 
between 800 and 1,600 meters. At the western (landward) end of the 
profile aU the curves swing sharply upward, showing a very pronounced 



\ 



Salinity; %o 

34.9 35 .1 .2 .3 .4 .5 .6 .7 
Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 

Fig. 9.— Salinity sections between Bermuda and the Bahamas; stations 10183, 10185, 10187, 10191. 

banking up of cold water against the continental slope, which need 
be merely mentioned here, being discussed at length on page 47, 
and there was evidently a minor banking up of abyssal water against 
Bermuda below 1,200 meters. Down to the 700-meter level sahnity 
(fig. 12) agrees closely with temperature, the curve for 36°/oo 
practically coinciding with 15°, the warm surface water at station 
10164 finding its counterpart in high salinity (36.5°/oo). On the 
continental sloj)e the successive curves for sahnity dip, hke those 
for temperature, very steeply from west to east — i. e., they afford 



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16 EXPLORATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

further evidence of the banking up of abyssal water, and of water 
from the middepths, against the slope. The curves show that the 
salinity was rather higher in the middle of the profile than either 
farther west or farther east, instead of lower, hke the temperature; 
but on the slope of the Bermudas sahnity, hke temperature, sug- 
gests a shght upwelhng of abyssal water— i. e., it is only in the mid- 
layers that salinity and temperature fail to agree. Below about 



Salinity; %o 



Meter 

100 
200 
300 
400 
500 
600 
700 
800 
900 



200 
300 
400 



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600 
700 
800 

Fig. 10.— Salinity sections east of the Bahama Bank; stations 10193, 10210, 10212, and down to 1,800 meters 
in the northeast Providence Channel, station 10196. 

1,800 meters abyssal water with practically uniform sahnity (34.9''/oo) 
was encountered. 

The upper layers of water were*> colder over the southern slope of 
the Bermuda Bank (station 10179, fig. 13) than over the northern 
(station 10177, fig. 11), the difference being greatest (3°) at 1,200 
meters; but below 1,400 meters the northern slope was the coldest. 
Along the line running southwest from Bermuda (fig. 13) the 
surface layers grew gradually warmer toward the south, the curve 
for 15° dipphig from 550 to 700 meters, while near the surface the 



EXPLORATIOlSrS^ WESTERN" ATLANTIC, STEAMER BACHE, 1914. 17 

temperature rose from about 18° to 20°, and the peculiar S-shaped 
curve for 20° suggests an active mixing of cool and warm surface 
water. In the deeps, below 700 meters, the curves reveal a pro- 
nounced upweUing of cold abyssal water at station 10181, and the 
salinity profile (fig. 14) along this line shows much the same thing, 
the surface layers down growing salter, from north to south, while in 
the deeper layers sahnity, like temperature, curves rise at station 
10181. 

The temperature profile from Florida to a point 200 miles southwest 
of Bermuda (fig. 15) shows that water warmer than 20° was thickest 
near the Bahama Bank (about 200 meters). East of this the curve 
of 20° rises to 50 meters at station 10191, then dips, as a tongue, to 




Fig. 11.— Temperature profile of the upper 1,800 meters from Chesapeake Bay to station 10161; and from a 
point 130 miles south of the latter to Bermuda. 

150 meters at station 10189, where the surface was 19.6°. But 20° 
water is again seen at the eastern end of the profile. The curves for 
15°, 10°, and 5° are roughly parallel with each other, showing a suc- 
cession of cold and warm undulations, but, as a whole, dipping from 
'West to east, the former from about 500 to about 700 meters, the 
latter from about 1,100 to about 1,600 meters. The most striking 
of these undulations is a well-developed cold band some 300 miles 
southwest of Bermuda (station 10185), and this is evidenced by an 
upswing of the curves down to 1,800 meters, as well as by lowered 
surface temperature. Immediately east of it, however, the water, as 
a whole, is warmer than anywhere else along the profile. The tem- 
perature then falls toward the west from station 10187 to station 10212 ; 
but there is a well-marked warm band over the 1,800-meter contour on 
63271°— 17 2 



18 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

the slope of the Bahama Bank. The temperature sections along this 
line (fig. 5, 6) show that practically the entire cooling from the sur- 
face downward takes place in the upper 1,500 meters; and below 
about 1,800 meters the west-east dip is still evident. The profile 
illustrates sufficiently the contrast between the Antilles water on 
the one hand and the Florida current water on the other, for while 
the latter is even warmer than the former on the surface, water 
colder than 10° comes much nearer the surface in it, what we may call 
an entire oceanic section being compressed into a channel only some 
700 meters deep, and the banking up of cold bottom water on the left- 
hand side is much more extreme in the Florida than in the Antilles 
current. 



Stations 




Fig. 12.— Salinity profile of the upper 1,800 meters, Chesapeake Bay to station 10161, and from a point 130 
miles south of the latter to Bermuda. 

SaUnity (fig. 16) agrees very well with temperature along this 
profile down to 1,200 meters. Thus, the curve of 36°/oo is almost 
exactly parallel with that of 15°; the curves of 35.5°/oo and 
35.3°/oo roughly, though not exactly, parallel with 10° and 5° 
temperatures, respectively. Consequently, below 500 meters the two 
combined show a mass of warm water of high salinity south of Ber- 
muda; a band of cool, comparatively fresh water at station 101S5; 
next, a second warm salt mass about 300 miles southeast of Bermuda, 
followed by a general coohng and decline of salinity as far as the 
l,S00-meter contour on the slope, where there is a third well-marked 
warm salt band. Between the 500-meter level and the surface the 
general trend of the salinity curves is different, the saltest water as a 
whole lying northwest of the Bahama Bank, where there is a layer 
about 300 meters thick with sahnity above 36.57oo- Farther 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 19 

east this strikingly saline layer is much thinner and it is twice inter- 
rupted (stations 10189 and 10185), though it once more appears near 
Bermuda. Over the northern end of the Bahama Bank the 36.5%o 
water is overlaid by fresher water, as described for the Jupiter 
Inlet profile across the Florida current (p. 32). Below 1,200 meters 
there is very httle further decrease in sahnity: At 1,800 meters it 
ranges from 34.96 to 35.0P/oo only, and judging from what is 
known of Atlantic bottom water (Murray and Hjort, 1912; Nansen, 
1912), it is probably practically uniform below that depth. Though 
the curve of 35°/oo suggests a slight upwelhng of this abyssal 
water in the center of the profile, the entire range of variation of 



Stations 
179 181 




Stations 
179 181 



36 



Fig. 13.— Temperature profile of the upper 1,800 
meters, on a line running 200 miles southwest 
from Bermuda. 



Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1800 
1700 
1800 

Fig. 14.— Salinity profile of the upper 1,800 meters, 
on a line running 200 miles southwest from 
Bermuda. 




sahnity below the 1,000-meter level is so small that it is doubtful 
whether this was really the case. Certainly, temperature suggests 
nothing of the kind but just the reverse. 

The relationship of these profiles to one another may be illustrated 
further by charts of the temperatures and salinities at the 200, 600, 
1,000, and 1,800 meter levels. 

At 200 meters salinity was remarkably uniform, the extreme range, 
except for the cool, fresh water next the coast (station 10158, p. 45), 
being from 36.42%o to 36.55°/oo only. The temperature range (fig. 
17) was also very small, 18.1° to 19.3° over most of the area. 
Next the coast off Chesapeake Bay it was much colder (11.2° at 



20 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

station 10158); but east of station 10161 the temperature at this 
level was nowhere below 18°. Off the mouth of the Straits of Florida 
and off the northeastern slope of the Bahama Bank (station 10210) 




Fig. 15. — Temperature profile of the upper 1,800 meters, from Florida to a poiat 200 miles southwest of 

Bermuda. 

the 200-meter temperature rose to 20°, and it was even warmer (22°) 
in the northeast Providence Channel (station 10196). The course of 
the curve of 19° is worth notice, since it shows a tonguelike extension 




Fig. 16.— Salmity profile of the upper 1,800 meters, from Florida to a point 200 miles southwest of Bermuda. 

of warm water parallel with the coast, recalling the surface (fig. 1). 
But this phenomenon was limited to the upper 300 to 400 meters, 
for at 600 meters (fig. 18) the water was warmest (16°) west of 



EXPLOfiATlONS, WESTERN ATLANTIC, STEAMEE BACHE, 1914. 21 

Bermuda, over a roughly oval area with slightly colder (15°) water on 
the east, south, west, and, probably, on the north also. South of 
Bermuda the temperature was below 15°. And it was even colder 
(12°) off the Bahama Bank, falling to 10° in the northeast Providence 
Channel, and probably all along the continental slope, with a tem- 
perature of only about 5° off Chesapeake Bay at this level. The 
extension of a tongue of 12° northward from the Bahama Bank 
suggests that part of the cold water, which is banked up against the 
latter, is drawn here into the general northerly drift of the Antilles 




CAPE HATTERA^; 



BERMUDA 



Fig. 17. — Temperatures at 200 meters. 

current; but apparently the cold water at station 10185 was the 
result of local upwelling, not of a cold band. 

The distribution of salinities at 600 meters (fig. 19) suggests, 
although it does not parallel, the temperature, the water being saltest 
(over 36.1°/oo) west of Bermuda, where the curve of 36%o incloses 
a roughly oval area, which was probably limited by water of lower 
salinity on the north, as it certainly was on the east, south, and 
west. The low salinity of station 10185 is as clearly a local phenome- 
non, as is its low temperature. Over the southwestern part of the 
area in general the salinity was very uniform (36-36.08°/oo) ; but 



22 EXPLOEATIOKS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

north of the Bahama Bank and along the continental shelf the 
water was much fresher, its salinity falling to about 35.5°/oo off 
the northeast slope of the bank, as far as station 10212, *and in the 
Providence Channel, to 34.9°/oo in the exit of the Straits of 
Florida (station 10206), and to about 35.1%o off Chesapeake 
Bay. Thus, the low temperature and salinity which characterize the 
surface waters west of Bermuda (p. 6, 7) were limited to a shallow 
zone, this being the warmest and saltest area at the 600-meter level. 
Similarly the very high surface temperature at the mouth of the 



CAPE HATTER 




Fig. 18. — Temperatures at 600 meters. 

Straits of Florida and northeast of the Bahamas in general was 
equally superficial, cold water rising nearer to the surface there than 
over the oceanic basin. 

At^ljOOO meters conditions are*^ puzzling. It is clear that the 
temperature at this level was highest (12°-13°) northwest of Ber- 
muda, and that most of the area studied was about 10°, with cooler 
water near the coast — i. e., that the general distribution of temper- 
ature was essentially similar to that of the 600-meter level. But the 
low temperatures (about 7°) at stations 10181, 10183, 10185, and 
10171, suggest a tongue of cold water, extending from southeast to 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 23 

northwest, right across the area traversed by the Bache, which has no 
counterpart at the higher level. Its outline forbids the assumption 
that it can be northern water, unless in the form of an upwelling. How- 
ever, the existence of such a tongue depends on the temperature read- 
ing at station 10171, and as this is not accompanied by correspond- 
ingly low salinity, but the contrary, it is natural to wonder whether 
it is correct. Discarding this one reading, the warm (10°) water 
would hardly be indented on the southeast (fig. 20), and the tempera- 
ture curves would agree much more closely with the salinities. The 



% 



CAPE HATTER 




/ ••bakaHAs 



5==^, 



Fig. 19.— Salinity at 600 meters. 

lowest temperatures at this level were off Cape Hatteras (4°-5°) and 
off the Bahama Bank, and it is probable, though not certain, that 
there was a continuous belt of cold water all along the continental 
slope. Sahnity (fig. 21) like temperature at 1,000 meters was highest 
northwest and west of Bermuda, with a similar slight indentation by 
fresher water on the southeast. Although the salinity, unlike the 
temperature, is practically uniform over a considerable area east and 
northeast of the Bahama Bank— i. e., affords no evidence of upwelling 
on the slope — ^this apparent difference is not essential, because the 
comparative uniformity of salinity below 1,000 meters makes it a far 



24 EXPLORATIOlSrS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

less obvious index to upwelling than temperature at this or greater 
depths. At 1,800 meters the temperature was very nearly uniform, 
the extreme range being only from 3.5° to 4.2°, with water as warm 
as 4° for approximately 400 miles west of Bermuda. At this level 
the extreme range of salinity was only 0.07%o (34.94-35.01*'/oo), 
water of 35%o occupying an elipse between Bermuda and the 
Bahamas, apparently surrounded by slightly fresher water — i. e., 
roughly corresponding to the area of highest temperature at this 
level. Thus, the effect of the warm salt water of the Florida and 



CAPE HAHER 




f, BAHAMA 



■■'X 



Fig. 20.— Temperature at 1,000 meters. 

Antilles currents, so noticeable on the surface, is hardly to be traced 
below 600 meters, by either salinity or temperature. On the con- 
trary, the cold, comparatively fresh water of the deeps rises nearer 
to the surface under them than in the region west of Bermuda, and 
apparently this is also the case south and east of Bermuda. Thus 
we have, west of Bermuda, a mass of water distinguished by high 
temperature and salinity, from about 200 down to 1,800 meters. 

There is, of course, nothing novel in the observation that the water, 
as a whole, is warmer west of Bermuda than farther south or east — ^i. e., 
that the cold abyss water is farther from the surface. Indeed, the 



EXPLOEAMOFS^ WESTERN ATLANTIC j, STEAMER BACHE, 1914. 25 

general approach of the water of the abyss toward the surface, from 
about latitude 30° toward the Equator, is one of the most essential 
features of oceanic temperature and one of the most significant in its 
bearing on the general system of oceanic circulation. '^ 

It is interesting that while the 600-meter temperatures of the Bache 
agree very well with earUer records, the warmest water west and north- 
west of Bermuda being 16.3°-16.5°, as against 16.8° as given by Schott 
(1902), at 1,000 meters the Bache records are notably warmer, 13° as 
against 8.2°, according to Schott (1902, 1912) — that is to say, the 



CAPE HATTER 




BERMUDA 



Fig. 21.— Salinity at 1,000 meters. 

abyss water was farther from the surface — and even at 600 meters the 
area of 6° water extended farther to the south (to about 28° north 
latitude) than it is represented by Schott (about 31° north latitude), 
though hardly as far to the westward. Otherwise, the Bache and 
Valdivia charts agree very well for this level. Even at 1,000 meters, 
the geographic location of the absolute maximum is very nearly 
the same in Schott's chart as in our own. In short, the work of 
the Bache corroborates in general the earher temperature records; 
but the salinities are a distinct addition to oceanography, there 

a For an excellent account of Ihis phenomenon, see Schott (1912), p. 130. 



26 EXPLORATIOlSrS^ WESTERN ATLANTIC, STEAMEE BACHE, 1914. 

being practically no previous records for the niiddepths in this 
region. The discovery that the general distribution of salinity is the 
same as that of temperature — i. e., highest west of Bermuda (except 
on the immediate surface) — is a further corroboration of the upweUing 
of abyssal water toward the Equator. 

THE STRAITS OF FLORIDA. 

The Straits of Florida are historic grounds for oceanographic study, 
thanks to the temperatures taken by the Blake (Agassiz, 1888) and to 
the numerous cm-rent measurements made by the United States Coast 
and Geodetic Survey, especially by Capt. Pillsbury (1886, 1887, 1889). 
However, it remained for the Bache to obtain satisfactory series of 



4 5° 6 7 8 9 



Temperature, Centigiade 
10° 11 12 13 14 15° 16 17 18 19 20° 21 22 23 24 25* 



Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 

Fig. 22.— Temperature sections on the line Key West-Habana; stations 10197, 10198, 10199, 10200, 10201; 
and off Pensacola, Fla., March 13, 1885 ( , Albatross). 

salinities, simultaneous with temperatures. Three profiles were 
drawn across the Straits — one from Key West to Habana, one from 
Cape Florida to Gun Cay (coinciding with the Blalce and with Pills- 
bury's profiles) , and the third from off Jupiter Inlet to the northern 
end of the Little Bahama Bank. 

The Baclie found a general rise in surface temperature, from north 
to south, along the whole length of the channel, the water being warm- 
est (24.70°) approximately 20 miles from Habana — i. e., in the posi- 
tion of the axis of the Florida current at low declination of the moon. 
The surface was cooler immediately off Key West than anywhere else 
in the Straits (station 10197, 20.78°) with a slight but progressive 
warming along the Florida coast from southwest to east and north. 





























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EXPLORATIONS, WESTEEK ATLANTIC, STEAMER BACHE, 1914. 27 

Water warmer than 24° was confined to the southern and western 
part of the channel, and the water in the Old Bahama Channel was 
probably as warm as 24°, while the surface was fractionally cooler 
along the western face of the Bahama Bank. At the northern end 
of the channel the surface temperature was 23.6°-23.7°, and it was 
considerably cooler east of the Bahama Bank, as pointed out (p. 6). 
Thus, the inequalities in surface temperature are gradually dissipated 
from west to east and north, the temperature range diminishing 
from 4° off Habana to practically zero off Jupiter Inlet. As a whole, 
the Straits were considerably warmer on the surface than the Atlantic 
water east of the Bahama Bank. 



Meter 

100 

200 

300 

400 

500 

600 

700 

800 

900 

1000 

1100 

1200 

Fig. 



34,9 35 , 


1 
II 


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23.— Salinity sections on the line Key West-Habana; stations 10197, 10199, 10200. 



The surface salinity was much more uniform than the surface tem- 
perature, the extreme range over the whole length of the channel 
being about 0.27%o only (35.9° to 36.17%o). 

The serial observations on the Key West-Habana line (fig. 22, 23) 
show that off Key West the water cooled from nearly 21° on the 
surface to 11° at 200 meters; 20 mUes farther south from 23° to 14°,- 
in the center of the channel only from 23.5° to 22° in the same depth. 
Below that depth the curves of the temperature sections on this line 
approach each other, the temperature range at 900 m'eters being 
only 1.5° (7°-8.5°). The warmest station was in the center of the 
Strait (station 10201). UnfortunatePf, serial water samples were 
taken at only three of these five stations (none at station 10201, 
perhaps the most interesting of all). However, they show that the 
salinity was lowest umnediately off Key West (station 10197), and 



28 EXPLOEATiONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

that in the southern half of the channel (stations 10199 and 10200) 
the saltest water (about 36.5Voo) was at 200 meters, with 36%o 
water on the surface above it. Below the 200-meter level there 
was a rapid vertical decline of salinity to about 35-35. 2^/oo at 600 
meters, followed by a much slower decrease, to about 34.9°/oo 
at 1,100-1,200 meters. The temperature and salinity profiles (fig. 
24, 25) constructed from these sections show that water colder 
than 10°, and with salinity lower than 35'*/oo, was banked up 
against the Florida slope to within 200-300 meters of the surface. On 
the Cuban side of the profile water of 35°/oo was met only below 
about 900 meters (10° water at 700 meters). The coldest water of 
all (4°-5°) lay on the bottom off Habana below 1,300 meters, and 
water equally cold may have filled the trough below this depth, but 



Stations 
198 201 




Fig. 24. — Temperature profile, Key West-Habana. 

we have no records from this or greater depths on the north side. 
Perhaps the-most striking feature of the profile apart from the cool 
fresh water off Key West is the band of warm water at 100-800 
meters in the center of the channel outlined by the curves for tem- 
peratures between 10° and 20°. In the middepths this band was 
even warmer than the water next to the Cuban coast; but the surface 
water was warmest on the Cuban side where there was a surface layer 
about 100 meters thick of 24°-25°.^ 

Unfortunately, the salinity profile is not complete, there being 
no salinities for the middepths at stations 10198 or 10201; hence it 
is a question 'whether the wq,rm band just mentioned was charac- 
terized by high salinity as well as by high temperature. There is 
nothing in the data from the other stations along this Ime to forbid 
such an assumption. The range of surface salinity was only about 



EXPLOEATIONS^ WESTEEF ATLANTIC^ STEAMER BACHE, 1914. 29 

0.17%o (from 35.93 to 36.1°/oo), the surface being freshest on the Cuban 
side, above the saltest water (36.5%o), as just noted. 

Apart from a possible salt tongue in the center of the channel, the 
sahnity curves as a whole dip from north to south, and it is worth 



Stations 
198 201 




Fig. 25. — Salinity profile, Key West-Habana. 



noting that the same vertical range of salinity (36 to 35''/oo) which 
occupies 900 meters at the southern end was condensed into 250 
meters at the northern /end of the profile. 



Meter 



7 8 9 



Temperature, Centigrade 

10° 11 12 13 14 15° 16 17 18 19 20° 21 2 2 53 24 25° 




Fig. 26.— Temperature sections on the Gun Cay-Cape Florida line; stations 10202, 10203, 10204. 

Between Cape Florida and Gun Cay the channel is only about 900 
meters deep and 60 miles wide. Nevertheless, we find as great a 
range of sahnity (fig. 27) and almost as great a range of temperature 
(fig. 26) as m the Key West-Habana profile. As before, the water 
was coldest and freshest next to Florida, warmest and saltest off 
the Bahama Bank; and the two eastern stations are saltest (36.5°/oo) 



30 EXPLOEATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

at 200 meters, below which level there is a rapid decrease of salinity 
to 34.85%o at 800 meters in the center of the channel, and to 35.5*^/oo 
at 700 meters off Gun Cay. 

At aU three stations along this line the vertical cooling was rapid, 
the temperature dropping off Cape Florida from 21° to 10.5° in a 



Meter 



Salinity; %o 
34.8 35 .1 .2 .3 .4 .5 .6 .7 .8 .9 36 .1 .2 .3 .4 .5 .6 .7 




Fig. 27.— Salinity sections on the Gun Cay-Cape Florida line; stations 10202, 10203, 10204. 

distance of 50 meters; from 24° on the surface to 6° at 800 meters 
in the center of the channel; from 23° to 12° in 700 meters off Gun 
Cay. The temperature profile (fig. 28) shows no trace of the warm 
tongue so conspicuous between Key West and Habana, and the 
warmest water (24°-25°) was on the surface in the center of the 




Fig. 28.— Temperature profile across the Straits of Florida, Gun Cay-Cape Florida. 



channel, instead of on the Bahaman side, besides being fractionally 
cooler than the highest surface temperatures off Habana. The 
banking up of water colder than 10° and fresher than 35*^/00 
against Florida is even more pronounced than in the preceding 
profile, water with these characteristics rising to within about 175 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 31 

meters off Cape Florida; to about 250 meters off Key West. The 
same lenticular mass of 36.5%o water (fig, 29) is to be seen on 
the Bahaman side and at the same level (200 meters), as off Cuba 
in the Key West-Habana profile. As in the latter, the surface is 
freshest where warmest, though this is now in the center of the 
Strait uistead of on the Bahaman side. The whole range of surface 
salinity is only about 0.1%o- The curves for temperature colder 
than 20°, and salinities lower than 36%o, dip regularly from 
west to east, the curves for 36°/oo and 15° coinciding almost 
exactly with each other, an^ the slope growing progressively steeper 
with decrease of temperature and salinity. The saltest and coldest 
water was in the deepest part of the channel, 34.85°/oo and 6.16° at 
800 meters. 



Stations 



Meter 




Fig. 29.— Salinity profile across the Straits of Florida, Gun Cay to Cape Florida. 

Comparison between these two profiles shows that the subsurface 
temperatures between Cape Florida and the Bahama Bank agree 
very closely with those of the northern half of the Key West-Habana 
profile, the curve for 20° dippmg from 25 or 30 meters near Florida 
to about 250-275, the curve for 15° to about 500 meters in both, 
but below 500 meters the Cape Florida profile is considerably the 
colder of the two, depth for depth, its 800-meter temperature being 
about the same as at the 1,200-meter temperature between Key 
West and Habana. There was probably a shnilar difference in 
salinity, though owing to the lack of data at stations 10198 and 10201 
complete comparison is not possible. 

We find the same general type of temperature and sahnity sections 
(fig. 30, 31) along the Jupiter Inlet-Bahama Bank line, the water 
saltest at 200 meters, warmest on the surface, with the same general 
rise in temperature and sahnity from west to east. The total range 
of both is as great as before, but the depth of the channel having 



32 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

decreased to only 700 meters, the vertical increase is even more rapid 
than on the Cape Florida line. 

In the profiles (fig. 32, 33) the curves for 15° and 10° tempera- 
tures and for salinities of 36%o and less dip from west to east, water 
of 10° and 35°/oo rising to within about 200 meters of the surface off 

Temperature, Centigrade 
5° 6 7 8 9 10° 11 12 13 14 15° 16 17 18 19 20° 21 22 23 24 




Fig. 30.— Temperature sections between Jupiter Inlet and the Bahama Bank, and east of the latter; 

stations 10205, 10206, 10207, 10208. 

Jupiter Inlet; and as was the case off Cape Florida, the curves for 
15° and 36%o coincide with each other, but the curve for 20° 
temperature, which likewise dips near Florida, runs practically 
horizontal from the center of the channel eastward across the Bahama 
Bank. The mass of 36.5°/oo water once more appears at 200 meters; 

Salinity; %o 
.5 .6 .7 .8 .9 36 .1 .2 .3 .4 .5 .6 




Fig. 31.— Salinity sections between Jupiter Inlet anh. the Bahama Bank, and east of the latter; stations 
~^ 10205, 10206, 10207, 10208. 

but instead of being limited on the east by a coast line, as was the 
case in the preceding profiles, it now extends across the northern 
end of the Bahama Bank, to join the 36.5°/oo surface water farther 
east (fig. 16). There is no surface water as warm as 24° in this 
profile; but the difference between the warmest readings in it and 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 33 

the preceding profile is only fractional, while the surface was more 
uniform, and the mean surface temperature was fractionally higher 
(23.7°) along the Jupiter Inlet than the Cape Florida line (23.04°). 
In the bottom of the channel the water was of practically the same 
temperature (5.7°) and salinity (34.85Voo) as between Cape Florida 
and Gun Cay, 100 meters deeper. 




"Fig. 32. — Temperature profile running east from Jupiter Inlet, across the northern end of the Bahama Bank. 

The vertical condensation of salinity and temperature, and the 
general rise of cold fresh bottom water toward the surface from off 
Habana to the northern entrance of the channel is illustrated by an 
artificial profile lengthwise of the axis of the channel (fig. 34), recon- 
structed from the preceding transverse profiles. Several features 
deserve mention. The very warm surface water has been sufficiently 
emphasized. Beneath it lies a band of Salter, cooler water (36.5°/oo 



Stations 



Meter 




1000 
Fig. 33. — Salinity profile, running east from Jupiter Inlet, across the northern end of the Bahama Bank. 

and 20°) extending the whole length of the profile, and continu- 
ous in both calmity and temperature with the surface water east 
of the Bahama Bank (p. 19, fig. 15, 16). Whether it is also con- 
tinuous with the surface water of the Gulf of Mexico is not certam. 
Finally, at the northern end of the profile the rise of water of 6°-10° 
temperature and 34.8-35%o salinity toward the surface is very 
evident; but water colder than 5° does not rise up the slope 
above the 1,100-meter level. Water of this temperature was also 
63271°— 17 3 



34 EXPLORATIONS, WESTEEN ATLANTIC, STEAMEE BACHE, 1914. 

encountered at about this same level east of the Bahamas and also 
in the Providence Channel (station 10196). 

The distribution of temperature and salinity may be further 
illustrated by charts of the 200, 400, and 600 meter levels. 

At 200 meters (fig. 35) there was a general rise of temperature 
from north and west to south and east from about 10° close to the 
coast of Florida to 23° off Habana and 21.8° off Gun Cay. Opposite 
Jupiter Inlet, however, the warmest water (20.13°) was in the center 
of the channel at this level, with a fractionally lower reading (19.93°) 
off the northern end of the Bahama Bank. The range of salinity at 



Stations 



201-202 




Fig. 34.— Profile of salinity ( ), and temperature ( 

Horizontal scale. 



_), lengthwise of the Straits of Florida. 



this level was only 1.377oo (35.3 to 36.67°/oo) with the water freshest 
close to the coast of Florida, while the salinity of the southern and 
eastern haK of the channel ranged from 36.5 to 36.67%o (fig. 36). 

iU 400 meters (fig. 37) there wW a general west to east warming 
in the northern half of the channel from about 9° near Florida to 
16° near the Bahama Bank; but off Key West this was complicated 
by the warm tongue of 17° in the center of the channel, already 
described for the Key West-Habana profile. At this level the range 
of salinity (fig. 38) was from 35.17oo (station 10206) to 36.2%o; 
lowest close to the coast of Florida, highest on the south and 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 35 

east side of the channel, the curves for 35.5 and 36''/oo suggesting, 
although they do not precisely reproduce, the curves for 10° and 
15° temperatures, respectively. The lack of data from the mid- 
depths at station 10201 leaves the possibility open that there 
may have been a tongue of still salter water at the west end of the 
channel, to correspond with the tongue of high temperature there. 




ilTTLr-v:- 
BAHAMA 

\BANK 




\ GREAT 
\ BAHAMA \. 
.= BANK 



2 




CUBA 



Fig. 35.— Temperature in the Straits of Florida at 200 meters, March, 1914. 

At 600 meters, however (fig. 39), the warm water at station 10201 
has lost its tonguelike character, being continuous with the general 
temperature (12°-13°) of the southeastern and eastern parts of the 
Straits. At this level the water was 7°-10° along the Florida side 
of the channel, and there was a second cold area off Habana (9°-10°), 
apparently a tongue from the west. 



36 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

At 800 meters the distribution of temperature was much the same, 
coldest off Florida, and again off Habana, warmest in the center of 
the channel between Key West and Habana, and on the east side of 
the Straits, but the absolute value everywhere l°-3° lower. Below 
800 meters there was a general rise in temperature from north and 
west to south and east. 




IBAHAMA 
■\BANK 




.GREAT 

BAHAMA 

BANK 




CUBA 



Fig. 36.— Salinity in the Straits of Florida at 200 meters, March, 1914. 

Owing to the insufficiency of the records on the Key West-Habana 
line, it is not possible to plot the 600-meter salinity. In the northern 
half of the channel it ranged from about 34.9Voo off Florida to 35.6°/oo 
off the Bahama Bank, the curve for 35°/oo running, roughly, north 
and south. Judging from stations 10200 and 10199, where the 
sahnity, respectively, was 35 and 35.27%o, and from station 10197, 



EXPLOEATIOlSrS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 37 

where it was 35.3**/oo at 200 meters, there was probably a general 
rise, north to south, from below 35°/oo to about SS.S^/oo at 600 meters, 
at the west end of the Straits as well. This rise in salinity, from the 
Floridan to the Cuban and Bahaman side of the channel, is still 
traceable at 800 meters, where the salinity rose from 34.85-34.9*'/oo 
at stations 10200 and 10203 to 35.1°/oo off Habana and 35.4%o off 
Gun Cay. 




ilTTLt- ■■•■■• 
.BAHAMA 
\BANK 




Ul 



GREAT 
\ BAHAMA 
IBANK 




CUBA 



Fig. 37.— Temperature at 400 meters in the Straits of Florida, March, 1914. 

The future must show whether the salinities outlined above are 
normal for the Straits, there being no rehable data for comparison; 
neither, for that matter, are the subsurface saHnities known for any 
part of the GuK of Mexico, the various hydrometer readings which 
have been taken there bemg too high (Kriimmel, 1907, p. 357), nor 



38 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914 



^ 



for the water immediately north of the Bahamas. But the Blake 
temperature series taken in 1878 between the Tortugas and Cuba, 
and on the Cape Florida-Gun Cay hne, reveal the same general dip 
of the temperature curves from north and west to south and east, 
and the same banking up of cold water against Florida that charac- 
terize the profiles run by the Bache. 




IBAHAMA 
■■-..BANK 




^ GREAT ... 
\ BAHAMA \ 
IBANK 




CUBA 



Fig. 38. — Salinity at 400 meters in the Straits of Florida, March, 1914. 

At the western end of the Straits the temperatures for the two 
years agree very closely off Cuba (fig. 40) and on the Florida side 
(fig. 41), except that the immediate surface was warmer in May, 1878, 
than in March, 1914, as might have been expected from the differ- 
ence in season. Otherwise the only notable deviation in the curves 
is that the 1,800-meter temperature was 5° higher in 1878 thaninl914, 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 39 

the water between 700 and 1,300 meters 1°-1.5° colder; and in the 
center of the channel (fig. 42) the water was considerably colder in 
the middepths in 1878, the warm band so notable in the Bache 
profile being absent. Consequently, the temperature curves in the 
Blake profile (Agassiz, 1888, p. 231, fig. 157) dip more regularly from 
north to south. 




CUBA 



LITTLE v, 

BAHAMA 



\BANK 




GREAT 
\ BAHAMA 
/BANK 




Fig. o9.— Temperature at 600 meters in the Straits of Florida, March, 1914. 

The Blake profile (Agassiz, 1888) on the Cape Florida-Gun Cay 
liae shows that water colder than 10° was much nearer the surface 
in 1878 than in 1914, although the temperature in the bottom of the 
channel was very nearly the same (5.5° to 6.1°) for the two years. 
Near the surface, however, the Blake temperatures taken in May 
were higher than the Bache readings in March, the temperature sec- 



40 EXPLOEATIOXS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

Temperature, Centigrade 
Meter 0'*—*°^ 7 8 9 10° 11 12 1 3 14 15° 16 17 18 1 9 2 0° 21 22 23 24 25° 26 27 
100 
200 

300 

400 

500 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
Fig. 40.— Temperature sections taken off Habana, Cuba,March, 1914, by the Bache 
and off Port Miiriel, Cuba, by the Blake, May 12, 1878 ( 



i 









































200; 




/ 










































,.'•• 




^ 


































T^ 


rr^ 




































^ 


■rr-- 


ss^ 






































^ 




:^- 










































A 














































i 


' 












































/ 


J 














































/ 


; 












































J 




/ 












































/ 


/* 


f 










































/ 
















































I- 














































,'/ 
















































7 

















































(station 10200), (. 
)• 



I ' I I I I I I I I I I I I L-.-'l I 



Temperature, Centigrade 

n* . » 6 7 8 9 10° 11 12 13 14 15° 16 17 1 8 19 20° 21 22 23 24 25° 
Meter "^ — 

100 

200 

300 

400 

500 

Fig. 41.— Temperature sections taken ofE Key "West by the Baclie (stations 10197, 10198), March, 1914, (, ), 

and off the Tortugas by the Blake, May 11, 1878 ( _). 

Temperature, Centigrade 

»5° 6 7 8 9 10° 11 12 13 14 15° 16 17 18 19 20° 21 22 23 24 25° 26 27 
Meter 

100 

200 

300 

400 

500 

600 

800 

900 

1000 

1100 

Fig. 42.— Temperature sections in the center of the Straits, between Florida and Cuba, by the Baclic 
(station 10201), ( ), and by the Blake, May 11, 1878 ( ). 



































^ 


Jol. 


7" 




i 


T 










































/ 




































— **- 






























^ 


-^ 








,, 


-'' 


























^ 


-^ 










_,.. 


,-•' 


























,^ 


y 










..-* 


" 




























/• 
















V 


























/ 










































/ 












































/ 

























































































EXPLOKATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 41 

tions showing tliat seasonal warming had progressed down to about 
100 meters at that season. 

The fact that cold water was banked up against Florida in both 
years is evidence that the general distribution of temperature encoun- 
tered by the Bache is the normal condition for the Straits; but there 

Temperature, Centigrade 
5» 6 7 8 9 10° n 12 13 14 15° 16 17 18 19 20° 21 22 23 24 25° 26 27 28 



Meter 
100 
200 
300 
400 
500 
600 
700 
800 

~FiG. 43.— Temperature sections in the middle of the Straits between Gun Cay and Cape Florida, Bache 
(station 10203), , and by the Blake, May 30, 1878, . 

are evidently considerable variations from year to year in the abso- 
lute temperature in the middepths, which probably depend on varia- 
tions in the deep-water currents of the Straits. 

It is, of course, common knowledge that a very strong surface cur- 
rent flows out of the GuK of Mexico via the Straits of Florida," but 

Temperature, Centigrade 
7 8 9 10° 11 12 13 14 \f\%~\l 18 19 20° 21 22 23 24 25° 



,/ ^ — — ^ 

-C. y^Z — ^ 



erO 


































/■ 


^m* 


'" 




100 
































'/" 


f'' 








200 




























:*^ 


y 












300 
























\'^ 


















400 




















'^ 


^ 




















500 














,.- 


.-t^ 


•J^ 
























600 










... 
































;oo 






,• 


,.' 


































800 


^t 


•* 






































900 


#"* 








































1UU0 











































Fig. 44.— Temperature sections 40 miles northeast of Habana, March, 1914, BacU (station 10201), 

and about 95 miles northwest of Habana, May 17, 1876 [Blake) 

information as to the movements of the water in the deeper parts of 
the Straits is scanty. Mitchell (1869), it is true, beheved that he 
found both velocity and direction constant down to 600 fathoms 
off the Cuban coast, and his conclusion was accepted by Alexander 

a For an excellent summary of the history of the Gulf Stream, see Kriimmel (1911), p. 574. 



42 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 



1 



Agassiz (1888). The explorations by the United States Coast and 
Geodetic Survey (Pillsbury, 1886, 1887, 1889) show that an imper- 
fect method of observation had much to do with this result, meas- 
urements with current meters at numerous stations demonstrating 
that as a whole the current was strongest on the surface, decreasing 
progressively with depth; and although it was still perceptible and 
sometimes as strong as the surface current at 130 fathoms (237 
meters), the lowest level at which readings were regularly taken, 
the rate of decrease suggested comparative stagnation below about 
250 fathoms (457 meters) . Although the Bache made no actual current 
measurements, yet the difficulties encountered in using the oceano- 
graphic apparatus showed that the current ran very much more 
rapidly on the surface than in the middepths. 



Meter 

100 
200 
300 
400 
500 
600 
700 
800 
900 
1000 
1100 
1200 



5° 6 7 8 



Temperature, Centigrade 
9 10° 11 12 13 14 15° 16 17 18 19 20° 21 22 23 24 25» 



A^ __ —m — .— .^—- 



Fig. 45.- 



-Temperature sections oft Habana, March, 1914. Bache (station 10199), , and off Cape San 

Antonio, May 22, 1878 {Blake) ( ). 



But densities show that the water can not be stagnant in the 
bottom of the channel, for water of 1 .03 is higher at its exit than 
at its entrance, a state of instability which can only be main- 
tained in one of two ways — i. e., either by a movement of abyssal 
water from the Gulf of Mexico up the slope of the channel, or by a 
cold bottom current from the Atlantic. The last supposition has 
nothing except the persistent and still popidar tendency to credit 
all cool water along our coasts to the Labrador current ° to support 
it. Qa the contrary, as Agassiz long ago pointed out, the fadt that 
the general temperature of the Straits is the same as that of the 
mass of water west of it, but considerably lower than that of the 
Atlantic water into which it debouches, in itseK seems to forbid the 
possibility that the cold water in the Straits of Florida comes from 
the north". A study of the Blake temperature sections on successive 



a Sumner (1913); Soley (1911). 



EXPLORATIONS, WESTEEN ATLANTIC, STEAMER BACHE, 1914. 43 

lines normal to the coast, from Cape Canaveral northward (Agassiz, 
1888, iig. 176), shows that except on the immediate surface the Gulf 
Stream retains its character as a cool current as far as Cape Fear, 
beyond which it is indistinguishable from the water farther to the 
east. Furthermore, the evidence of salinity is, if anything, even 
more conclusive, because while the bottom water of the channel 
(34.8-34.9Voo) is continuous with the abyssal water off Habana 
at its west end and hence of the GuH, off the Bahamas water of this 
salinity was encountered only below 1,800 meters, a vertical drop 
of 1,000 meters from the exit of the channel. Hence, to suppose 
that the bottom water of the Straits enters from the Atlantic abyss, 
we must assiune a vertical upweUing of 1,000 meters, of which there 
is no evidence whatever. And it can not be coastal water from the 
north, because far too salt. In short, it is clear that the bottom 

Stations 




Fig. 46.— Profile of density, at temperature in situ and corrected for pressure, across the Straits of Florida, 

Gun Cay to Cape Florida. 

current in the Straits must flow in the same direction as the surface 
current — i. e., from the Gulf of Mexico — driving the heavy abyssal 
water of the latter (1.03+) up the slope, thus producing the 
density gradient mentioned above. This bottom current must be 
constant, or nearly so, since the rise of cold comparatively fresh 
water from the deeps of the Gulf up the rising floor of the Straits to 
near the surface at its exit is now shown to be a permanent phe- 
nomenon. In short, the countercurrents occasionally detected by 
Pillsbury on the bottom on the Florida side of the channel at about 
100 fathoms, hke the surface countercurrents so long recognized by 
mariners, are merely local reaction phenomena, or eddies. How- 
ever, the velocity of the bottom current is certainly only a fraction 
of the surface drift; and it may be very small indeed. 

The close agreement between the salinity of the bottom of the 
Straits and that of the water in the Atlantic abyss is not the least 



44 EXPLOEATIOlSrS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

interesting discovery made by the Bache, for it shows that the 
salinity of the water which flows into the Caribbean Sea through the 
bottom of the Windward Passage (between Cuba and Haiti), the 
Anegada Passage (between Sombrero and the Virgin Islands), and 
possibly the passages between Dominica, Martinique, St. Lucia, and 
St. Vincent, and thence into the Gulf of Mexico via the bottom of 
the Yucatan Channel, is unaltered during its sojourn there, a gen- 
eralization which also holds for temperature, as pointed out by A. 
Agassiz (1888, p. 220). 

The vertical distribution of temperature in the upper layers on 
the southern half of the Key West-Habana line is generally similar 
to that of the southwestern part of the Gulf and Straits of Yucatan. 
In spite of the interval of 40 years between the two sets of observa- 
tions, the temperature at Bache station 10021 agrees almost exactly, 
down to 800 meters, with the temperature encountered by the Blake 
on May 17, 1876, about 95 miles northwest of Habana, except for 
being cooler at the immediate surface, a difference to be expected 
because of the different seasons. And the slightly cooler water off 
Habana (station 10199) was almost exactly identical with the tem- 
peratures taken by the Blake in 1878 on the east side of the Yucatan 
Channel close to Cape San Antonio, except, as before, for a seasonal 
difference on the immediate surface. 

The much colder and fresher water off Key West must have a 
twofold origin. Probably it comes chiefly from the current which 
flows around the northern and eastern sides of the Gulf, following 
the 200-meter curve (British Admiralty, 1897; Soley, 1911). This 
current is considerably colder at all depths down to about 800 meters 
than the water in the central and southern parts of the Gulf," as 
shown by temperatures taken off Apalachicola, Fla., by the United 
States Fish Commission steamer Albatross"' on March 13, 1885, 
receiving its low temperature from the cold water in the north- 
western part of the GuK (Krtimmel, 1907). The water is even 
colder on the surface at this season along the north shore of the 
GuH than in the Straits. However, this cold surface is confined to a 
very narrow belt (Deutsche Seewahrte, 1882) and is probably due to 
the cold "northers" which blow so often in winter. 

The fact that, except for this shallow surface layer, the water was 
considerably colder close to Key West than the Albatross found it 
in the northern part of the Gulf (fig. 26), indicates that some up- 
weUing was taking place from the deeps of the Gulf. Thus, tempera- 
tures suggest that the v/est end of the Straits is a condensed epitome 
of the Gulf as a whole, water from the north flowing around the 
Florida cays, from the center of the Gulf into the center of the 

a Dredging and otherrecords of the United States Fish Commission steamer Albatross, etc.; Townsend, 
C. H.; Report United States Commission of Fish and Fisheries, 1900, p. 494. 



EXPLORATIONS^ WESTEEN ATLANTIC, STEAMER BACHE, 1914, 45 

Straits, and from the southern part of the GuK along the shore of 
Cuba, into the southern side of the Straits, as into a funnel. Up- 
welling of bottom water against the coast of Florida grows more 
pronounced as this tremendous mass of water forces its way farther 
and farther into the ever narrowing and shoaling channel. 

The unity of temperature between the western end of the Straits 
in 1914, and the Gulf of Mexico as a whole in 1878, is further 
interesting because it shows that the difference of temperature in 
the eastern end of the Straits in the two years can not have been due 
to any intrinsic difference in the reservoir from which the water 
came, but must have been the result of a greater flow of cold bottom 
water in 1878 than in 1914. For all that is yet known, this may be 
a seasonal, not a vicarious or periodic, variation. 

The banking up of cold water against Florida is usually classed as 
the effect of the rotation of the earth, forcing the water out of its 
course toward the right against Cuba and the Bahama Bank, with 
consequent upwellmg from the deep layers on the left-hand side of 
the channel, according to Ekman's (1905) theory (Kriimmel, 1911, 
p. 45^). The discovery that the cold comparatively fresh water 
next to Florida is largely true abyssal water from the Gulf of Mexico 
supports this view. The density profile. Cape Florida to Gun Cay 
(fig. 46), shows how much lighter, as well as fresher and colder, the 
water was on the left than on' the right side of the current,** an 
illustration of how effective the deflective force of the earth's rotation 
is in establishing the distribution of temperature and salinity in a 
current as rapid as the Florida stream. 

THE COAST WATER OFF CHESAPEAKE BAY. 

Exploration of the coast water was only incidental to the main 
work of the Bache, but stations 10157-10160 off the mouth of Chesa- 
peake Bay, and a series of observations taken on the continental 
shelf in that same general region in January, 1916 (p. 60), by the 
Bureau of Fisheries steamer Roosevelt, may be discussed here because 
of their bearing on the general problem of the origin of the coast 
water and its relationship to the Gulf Stream (Bigelow, 1915, p. 250). 

In January, 1913 (Bache stations), the temperature from the coast 
out to the 35-meter contour was between 6° and 7°, practically 
uniform from surface to bottom. The salinity, however, showed 
considerable vertical range even in the small depth of 18 meters 
(30.01^00 on the surface, 33.57%o on the bottom, station 10157), 
and at the 35-meter contour the freshest water lay at 20 meters 
(station 10159), with Salter water both above and below (fig. 48), 

f- For discussion of the general problem of the effect of the earth's rotation on ocean currents, see Ekman 
(1905) and McEwen (1912). For an excellent summary of the results on actual ocean currents, see Murray 
and Hjort (1912), p. 27C. 



46 EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 

instead of on the surface. Over the 200-meter contour, always an 
important zone off the United States coast because of the abrupt 
change in the slope of the bottom at this level, the temperature 
was highest at the middepth (station 10160, 100 meters, 12°), with 9° 
both on the surface and on the bottom, the latter several degrees 
warmer than the bottom temperature near the coast, in spite of the 
greater depth (fig. 47). The salinity (fig. 48) also was considerably 
higher, with a rapid vertical increase from the surface downward 
to 35.37%o on the bottom. Over the 1,800-meter contour, a few 



Meter 



Temperature, Centigrade 
8 9 10° 11 12 13 14 15° 16 17 18 19 20° 21 22 




Fig. 47.— Temperature sections off the mouth of Chesapeake Bay, stations 10158, 10160, 10161. 

miles outside the continental shelf (station 10158, fig. 47), the water 
was warmer, depth for depth, being nearly uniform at 11°-12° down 
to 300 meters, below which level there was a rapid cooling to about 5° 
at 70j0 meters, followed by a slow ^decrease of temperature to 3.55° 
at 1,800 meters. However, there was no water at this station 
(fig. 23) as salt as the bottom water over the outer edge of the shelf, 
the highest salinity being only about 35.1 9 Voo at 300 meters, with 
a slow decrease below this level. Near the surface the course of 
the salinity section is noteworthy, the water being freshest at 20 
meters, not on the surface. Eighty-five miles farther offshore (station 



EXPLOBATIO]SrS_, WESTERN ATLANTIC^ STEAMER BACHE, 1914. 47 

10161) the water was much warmer and Salter in the upper layers 
(maximum temperature 21.5°, salinity about 36.45 Voo)) with a 
steady decline with depth, the temperature at 1,800 meters being 
practically the same as at station 10158. Unfortunately, no water 
sample was taken at that level. The density (corrected for pressure 
by Ekman's tables of 1910) was lowest at the surface at aU these 
stations, greatest at the bottom (p. 60). 

The general temperature profile (fig. 11) shows that at this time 
the coast water over the shelf and on the continental slope was much 
colder than the oceanic water farther east at corresponding depths, 
the transition from one to the other being so sudden that the tem- 



2 .3 4 



Salinity; % 
.5 .6 .7 8 .9 35 .1 .2 .3 .4 .5 .6 .7 .8 .9 36 .1 .2 .3 .4 .5 



Meter 

100 

200 

300 

400 

5QDi 

600 

700 

800 

900 
1000 
1100 
1200 
1300 
1400 
1500 
1600 
1700 
1800 

Fig. 48.— Salinity sections off the moutli of Chesapeake Bay; stations 10158, 10160, 10161. 

perature curves dip very steeply from land to sea, a typical "cold 
wall." For example, the 5° curve rises from about 1,000 meters at 
station 10161 to about 500 meters on the slope in a horizontal dis- 
tance of 100 miles, and the uniform bottom water of the abyss (4°, 
and about 35%o) from about 1,800 meters over the oceanic basin 
to about 1,200 meters on the slope in the same distance. But the 
cold coast water (about 6°) was not continuous with the cold water 
of the abyss, being separated from it by a band of warmer water 
(9° -10°) washing the bottom at the 200-meter level, and the curves 
suggest that the bottom water was even warmer (10°-11°) at about 
250 meters. 







— 


— 


-S 


T- 




" 




























7 


















^ 






160 


\ 






















) 


















*^ 


~s 
























/ 


/ 




















/ 






















,/ 


/ 






















/ 




















/ 


/ 






















/ 




















y^ 


























/ 
















y 


y 




























158 












/> 


X 










































^ 


tei 






































^ 


^ 


^ 








































,' 


/ 












































/ 










































1 




; 










































/ 
























































































































































































i 

































48 EXPLOEATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 



The temperatures over the inner part of the sheK, both vertical 
and horizontal, were extremely uniform. 

Except for its demonstration that the cold coast and abyss waters 
were discontinuous, the temperature profile does not throw much 
hght on the movements of the water in this region; but the salinity 
projBle (fig. 49) is unusuaUy instructive in this respect. In general, 
sahnity, like temperature, was much lower near the coast than over 
the oceanic basin, with the same sudden transition from one type of 
water to the other. The distinction is even sharper in sahnity than 
in temperature, the coast water (33-35°/oo) being separated by a 



Meter 



lis /3S.4 




Fig. 49.— Profile of salinity, , and density at the temperature in situ, . 



., from the mouth of 



Chesapeake Bay, across the continental shelf, to a point 90 miles southeast of the 200 meter contour. 

zone of much Salter water some 1,000 meters thick from the abyssal 
water (34.9-35<'/oo). On the sheK itself there was a steady rise 
of sahnity from the land out to about the 100-meter contour, the 
curves for successive salinities showing that the axis of freshest water 
dipped from the surface next the land to about 30 meters at station 
10160, overlying considerably salter bottom water. It is over the 
200-meter contour that the profile is most instructive, for here water 
fresher than 35°/oo suddenly dips downward like a tongue into the 
Salter ocean water, and the bottom water of about 35.37Voo at station 
10260 seems to have been entirely surrounded by fresher water. 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 49 

Such a distribution of salinity obviously suggests that water was flow- 
ing down off the shelf into the ocean deeps, and densities are entirely 
in harmony with this explanation. Thus the water was decidedly 
denser — ^i. e., heavier — over the slope (stations 10258, 10260) than at 
corresponding depths either on the shelf (stations 10157, 10159, 
p. 59) or in the ocean basin to the east (station 10161, p. 59); hence, 
would naturally tend to sink. This is further illustrated by the 
profile (fig. 49), on which all the density curves from the surface 
down to 500 meters dip sharply toward the ocean basin over the 200- 
meter contour, and their gradient of about 100 meters in a distance of 
only 40 miles is steep enough to indicate a very potent dynamic 
cause for vertical circulation of this type. True, while such a dis- 
tribution of density suggests a downpour, it does not prove it, be- 
cause more or less similar densities might result from the opposite 
process — i. e., an upweEing of heavy water from the abyss over the 
slope. But when we add the facts that this dense water exactly 
^coincides with the fresh tongue just described, and that the tongue 
is absolutely separated from the abyss by considerably salter water 
in the middepths, there is no escape from the conclusion that a down- 
pour or waterfall was actually taking place. If any further con- 
'firmation be needed, it is supplied by the fact that the tempera- 
ture of the axis of this tongue of 34.5-35°/oo water (station 10158) 
was almost uniform (11 °-l 2°) from the surface down to 300 meters — 
i. e., to almost exactly the depth to which the curve for 35.2%o 
salinity dips — below which there was a rapid coohng to the consid- 
erably lower temperatures (4°-5°) of the abyss. Had up welling 
been active, just the reverse — i. e., a sudden vertical cooling in the 
upper layers — would have obtained. 

The sudden cooHng (fig. 47)'and the reversal of the vertical change 
in salinity (fig. 48) at 300-700 meters over the slope (station 10158) 
marks this zone as the lower limit to the downward flow. The imi- 
form abyssal temperature (about 4°) and salinity (about 34.9-35°/oo) 
was encountered here at about 1,200 meters; but in the ocean basin 
to the east, and, indeed, along the whole line to Bermuda, the upper 
limit to this abyssal water was at about 1 ,800 meters (p. 16, fig. 11, 12) . 
So uniform is this water over the north Atlantic as a whole (Ejiimmel, 
1907), and so closely do the curves for 35**/oo and 4° coincide, 
that this difference in level is only explicable as the result of upwell- 
ing over the lower part of the continental slope, the first time we have 
actually been able to demonstrate this type of circulation on any 
large scale off our coast (1915). So far as true abyssal water is con- 
cerned, this updraught did not rise above about 1,000 meters; but 
the close agreement between the salinity and temperature of the 
bottom water on the slope (station 10160) and of the water of the mid- 
zone at 1,300-1,400 meters to the east (stations 10161, 10163, 10166) 
63271°— 17 4 



50 EXPLORATIONS, WESTEElSr ATLANTIC, STEAMER BACHE, 1914. 

suggests that the latter also was involved, moving up the slope to 
within about 200 fathoms of the surface. All this, of course, suggests 
that upweUing from the middepths may play a r6le of some importance 
in the maufacture of the zone of mixed water along the continental 
slope, though there is no evidence that oceanic upwelHng ever reaches 
the continental shelf, as Petterson (1897), Clark (1914), and others 
have supposed. But while there may have been an updraught over 
the slope shortly previous to the cruise of the BacJie, nothing of the sort 
was taking place at that time, because the bottom water at station 
10260 was then entirely cut off from the equally salt midlayers by 
the lower salinities at station 10258 (p. 48). 




/ZOOM. 



34.5 %o 



Fig. 50.— Temperatures, 



-, and salinities, ■ 



-, off Chesapeake Bay at 20 meters, January, 1916 



{fioosevett stations). 



A simple explanation for the fact that the descending tongue did 
not actually follow the slope, but was separated from it by a layer of 
Salter, cooler water, is that the latter is merely a contrast phenomenon, 
the water preexisting along this part of the slope cut off by the down- 
pour^ The single Bache profile, unfortunately, is not sufficient to clear 
up this question. The existence of the downpour and of upwelling 
below 1,000 meters, however, is amply demonstrated. 

The more complete survey of the shelf abreast of Chesapeake Bay 
carried out by the Roosevelt in 1916 (p. 45, 60) shows that the tempera- 
ture was as uniform vertically in January, 1916, as in the correspond- 
ing month of 1914, the greatest vertical range at any station inside 



EXPLOEATIONS^ WESTERN ATLANTIC^ STEAMER BACHE, 1914. 51 

the 100-meter contour being only about 2° (p. 60), and that the 
temperature rose, passing offshore, from about 6°-7° near the land to 
10°-12° over the continental slope, just as in 1914 (fig. 50); but the 
coast water as a whole was l°-2° warmer at corresponding localities 
and depths in 1916 than in 1914.** Unfortunately the Roosevelt lines 
did not run offshore far enough to meet the warm ' ' GuK Stream ' ' water. 

The saUnities for the two years likewise agree, in so far as they rise 
from the land seaward (fig. 50), and in the flooding of the surface 
next to the land with water fresher than 30°/oo. But in 1916 the water 
over the shelf between the 20 and 100 meter contours was prac- 
tically uniform from surface to bottom, and the coast water as a 
whole was slightly Salter than in 1914. 

A difference far more important, if anything more than apparent, 
is that the profiles for 1916 (fig. 51, 52) do not show anything com- 
parable to the downpour outside the slope, so unmistakable in 1914; 
but it is possible that something of the sort would have appeared, 
liad the profiles run far enough offshore to reach the warm ocean 
water, jor the curves for 35%o and 35.2°/oo salinity strongly suggest 
the corresponding values for 1914 (fig. 49), so far as they go. 
Assuming the density of the ocean water to have been about the same 
in 1916 as in 1914, which was probably the case, there would have 
been the same dynamic tendency for the water over the slope to sink, 
in 1916 as in 1914, because the density was practically the same, at 
corresponding locations on the slope, for the Roosevelt as for the Bache 
stations (p. 59, 60). There is nothing in temperature to forbid it; on 
the contrary, the fact that water colder than 10° projected seaward 
from the shelf into the warmer water offshore in 1916 (fig. 51) dis- 
tinctly indicates a seaward flow at about the 50-meter level; and the 
temperature curves over the slope for the two years are readily 
reconciled with each other on the assumption that the seaward flow 
over the outer part of the shelf was localized in the upper 30 meters 
in 1914, as indeed salinity demands, whereas in 1916 it was rather 
deeper. In 1916 the slope, at 150-250 meters, was washed by water 
of 12°, a typical warm belt of the sort we are familiar with further 
north in summer (Bigelow, 1915), whereasin 1914 there was no bottom 
water warmer than 10° along this line. But as winter cooling seems to 
have progressed further by the end of January in 1914 than in 1916, 
this difference is, to all intents and purposes, a seasonal one. 

The salinity of the downward flowing tongue of January, 1914 
(34-34. 5%o), together with its comparatively low temperature, 
identifies it as the mixed water resulting from the contact of ocean 
with coast water. This contact, as is well known, takes place all 
along the continental slope as far north as the Grand Banks of New 

a The minimum temperature was lower in 1916 (station 8451, 5.8°) than in 1913 (station lOl^?, 6.2°); 
but this difference may be due to different geographic locations. 



52 EXPLORATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

Foundland. But whether the water thus manufactured tends to 
sink, or float, depends on the density resulting from the precise 
temperature and salinity at any given locality, compared to that of 
the upper 300 meters or so in the warmer, but Salter, water east of it. 
And, unfortunately, the relative densities of the two, off our coasts, 
are only known off Chesapeake Bay, and along a profile some 40 miles 



Meter 



Stations 

44 



45 46 




Fig. 51.— Temperature profile across the continen((;al shelf off Chesapeake Bay, January, 1916 {Roosevelt 

-^ stations 8442, 8443, 8444, 8445, 8446). 

east of Cape Cod, run by the Grampus in July, 1914, none of our 
other profiles across the slope having reached the undiluted ocean 
water. The density of the mixed water, however, is fairly weU known 
for the summer season from Chesapeake Bay to Nova Scotia (Bige- 
loWj 1915). But comparison between the two waters may fairly be 
extended beyond these actual records, for it is safe to assume that'' 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 53 



the ocean density at any given latitude is at least no higher in 
Slimmer than in winter; probably lower, because of solar warming, 
there being no reason to expect any great change in sahnity out- 
side the zone influenced by the coast. If this be true, there is the 
same dynamic tendency for the mixed water at the 50-150 meter 
level, over the slope off Chesapeake Bay, to sink in summer as in 



Meter 



42 



45 



Stations 

44 



33 



45 46 




Fig. 52.— Salinity profile across the continental shelf off Chesapeake Bay, January, 1916 {Roosevelt stations 

8442, 8443, 8444, 8445, 8446). 

winter, because the densities are practically the same there for the 
two seasons {Bache station 10158; Grampus station 10176, Bigelow, 
1915, p. 345) except on the immediate surface, where the water was so 
light in summer that it must have been floating out over the ocean 
water offshore (Bigelow, 1915). And summer densities were almost 
precisely the same, at the same relative position, off Delaware Bay 
(Bigelow, 1915, station 10171) as off Chesapeake Bay, in 1913 (fig. 53). 



54 EXPLORATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914.^ 

Only off Chesapeake Bay is the actual density of the mixed water 
known for winter. But inasmuch as winter cooling, off our coasts, is 
most rapid and most extreme next the land (Bigelow, 1915), while the 
salinity of the coast water, so far as known, rises during autumn and 
winter (Bigelow, 1915), it follows that the mixed is heavier than ocean 
water in winter all along our coast, as it certainly is off Chesapeake 
Bay (p. 49). 

But while the actual occurrence of a downpour over the slope can 
be considered as demonstrated off Chesapeake Bay in winter, and 
off Georges Bank in summer, our summer profiles across the shelf 
at intermediate points would be hard to reconcile with this type 
of vertical circulation (Bigelow, 1915). It is possible that a local 



Meter 

20 
40 
60 
80 
100 
120 
140 
160 
180 
200 
220 
240 
260 


Density 
24 5 25 5 26 5 2r 5 28 5 29 5 




" 







\ 
\ 




Vs 




















\ 

\ 




^ 


X, 




















\ 
\ 




\; 


\ 


















\ 




\ 


\ 




















N 


> 


. s 


\ 




















\ 




\ 




















\ 




\\ 






300 


















\ 

\ 


\ 


\ 




320 
340 


















\ 


V 


\\ 




3B0 
380 
400 




















\ 

61 \ 


\ 


> 



Fig, 53.— Density sections in the ocean water (Baclte station 10161), and in the mixed water (_Bac7ie station 
10158), ofE Chesapeake Bay, January, 1914, and in the mixed water (^Orampus station 10171), off Delaware 
Bay, July, 1913. 

dynamic tendency of this sort might be overridden by some more 
wide-spread type of oceanic circulation. But whether the down- 
pour be general for the zone over the continental slope, or only 
local or temporary, the fact that it actually occurs is one of the most 
interesting hydrographic results of the cruise of the Bache, for when- 
ever^nything of the sort takes plkce the mixed water must play as 
important a r61e in the manufacture of the deeper layers of the coast 
water on the shelf as it does in the Gulf of Maine. 

Finally, it is shown that there is nothing in the Bache or Roosevelt 
temperatures to suggest the * 'Arctic" current so often invoked off our 
coasts (Bigelow, 1915), the coast water being far too warm even in 
January. 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 55 
Table of Salinities and Temperatures; "Bache" Stations, 1914. 



Date. 


Station. 


Lat. N. 


Long. W. 


Depth. 


Salinity. 


Tempera- 
ture. 






o , 


o / 


Meters. 


o/oo 


" a 


Jan. 20 


10157 


36 46 


75 38 




18 


30.01 
33.57 


6.20 




6.75 


Jan. 21 


10158 


36 12 


74 25 



20 


34.94 
34.67 


12.30 




11.45 










100 


34.76 


11.15 










300 


35.19 


11.40 










700 


35.01 


4.78 










1,100 


35.01 


4.20 










1,800 


34.94 


3.55 


Jan. 26 


10159 


36 35 


75 20 



20 


33.04 
32.95 


7.00 




6.85 










36 


33.22 


6.75 


Jan. 26-27 


10160 


36 12 


74 41 



20 


34.29 
34.29 


9.15 




9.40 










100 


35.28 


12.00 










200 


35.37? 


9.45 


Jan. 27 


10160J 
10161' 










20 


36.08 
36.38 
36.35 


22.20 


Jan. 28 


"'35"27" 


"'73"i4' 


21.50 




21.50 










100 


36.44 


21.35 










200 


36.44 


19.60 










600 


35.99 


15.20 


^ 








1,000 


35.25 


10.40 




10162 
10162J 


34 41 
34 03 


73 23 
73 30 


1,800 






3.70 


Jan. 29 


'""36.' 44' 
36.49 


19.30 




18.80 




10163 


33 22 


73 37 




20 

100 

200 

600 

1,000 

1,800 


36.49 
36.53 
36.44 
36.49 
36.08 
35.41 
34.97 


18.95 
18.90 
18.85 
18.90 
15.70 
10.05 
3.80 


Jan. 30 


10163J 
10164 


33 02 
32 29 


73 38 
73 28 






36.44 
36.56 


19.90 




20.70 




10165 


32 32 


72 55 





36.53 


20.40 




10166 


32 33 


72 14 




20 

100 

200 

600 

1,000 


36.45 
36.47 
36.45 
36.42 
36.08 


19.15 
19.20 
18.80 
18.30 
15.80 
10.00 










1,800 




4.05 


Jan. 31 .... 


10167 
10168 


32 31 
32 28 


71 53 
71 41 






'"'36.' 49' 
36.53 


19.30 




19.10 


Jan. 31-Feb. 1 


10169 


32 29 


71 29 




20 


36.44 
36.38 


18.95 




19.00 










100 


36.44 


18.85 










200 


36.42 


18.83 










600 


36.26 


15.60 




10170 
10171 


32 18 
32 27 


71 12 
69 55 


1,000 

1,800 








10.50 




""ss.'oi' 

36.40 
36.45 




Feb. 2 


18.90 




18.95 










20 


36.44 


19.03 










100 


36.45 


18.84 










200 

600 

1,000 

1,800 


36.44 
36.08 
35.71 
34.99 


18.65 
16.10 
6.70 
4.00 


Feb.3 


10172 
10173 


32 26 
32 27 


69 21 
68 22 






36.45 
36.44 


18.90 


Feb.4 


18.85 










20 


36.44 


18.90 










100 


36.42 


18.70 










200 


36.44 


18.10 










600 


36.17 


16.50 










800 


35.64 


13.10 










1,000 
1,400 




11.60 




'"'35.' 46' 


5.55 










1,800 


34.96 


3.90 




10174 


32 28 


67 41 


3,650 

4,570 










'"'34." 87' 
36.44 




Feb. 5 ,. 


i8."96 




10175 


32 28 


66 28 



20 
100 

200 
600 


36.38 
36.38 
36.36 
36.45 
36.17 


18.90 
18.90 
18.90 
18.90 
16.30 




10176 


32 30 


65 48 


1,000 

1,800 












4.' 26 




""36." 44" 


19.20 



56 EXPLOEATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 
Table or Salinities and Temperatures; "Bache" Stations, 1914 — Continued, 



Date. 



Station. 



Lat. N. 



Long. W 



Depth. 



Salinity. 



Feb. 6. 



10177 



Feb. 17-18. 
Feb. 18.... 



Feb. 18-19. 
Feb. 19.... 



10178 
10179 



10180 
10181 



32 20 
32 12 



31 52 
31 01 



Feb. 19-20. 
Feb. 20.... 



Feb, 21. 



Feb. 21-22. 
Feb. 23 



Feb, 24, 



10182 
10183 



30 27 
29 32 



10184 
10185 



10186 
10187 



10188 
10189 



29 17 
29 16 



29 15 

28 59 



28 51 

28 48 



04 21 

64 42 



65 14 

65 58 



66 05 
66 25 



67 07 
67 51 



68 35 

69 22 



70 08 
70 40 



Meters. 



20 

100 

200 

400 

600 

1,000 

1,200 

1,500 

1,800 





20 

100 

200 

400 

600 

800 

1,000 

1,800 





20 

100 

200 

400 

600 

800 

1,000 

1,200 

1,400 

1,500 

1,800 





20 

100 

200 

400 

600 

800 

1,000 

1,400 

1,600 

1,800 





20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 





20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 





20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 



"loo 
36.42 
36.40 
36.44 
36.42 
36.35 
36.00 



35.05 



34.99 
36.42 
36.40 
36.44 
36.44 
36.42 
36.31 
35.90 
35.77 
35.37 
34.99 



36.42 



36.42 
36.44 
36.33 
35.93 
35.37 
35.07 
35.03 



35.01 
36.56 
36.62 



36.62 
36.53 



36.17 
35.73 



36.56 
36.42 



36.49 
36.35 
35.79 
35.21 
35.10 



35.01 
36.47 
36.51 



36.49 
36.47 
36.24 
35.70 
35.19 
35.05 
34.99 
34.99 
36.47 
36.47 



36.45 
36.45 
36.13 
35.55 
35.08 
34.99 
34.99 
34.97 



EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 57 
Table OF Salinities and Temperatures; "Bache" Stations, 1914— Continued. 



Date. 


StatioH. 


Lat. N. 


Long. W. 


Depth. 


Salinity. 


Tempera- 
ture. 


Feb. 25 


10190 
10191 

10192 
10193 

■ 

10194 
10195 

10196 
10197 
10198 
10199 

10200 

10201 
10202 


28 42 
28 33 

28 35 
28 43 

28 51 
29 

25 27 

24 18 
23 59 
23 13 

23 32 

23 47 

25 34 


71 32 

72 24 

73 33 

74 22 

75 13 

76 23 

77 16 
81 50 
81 50 
81 50 

81 48 

81 47 
79 24 


Meters. 





20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 



4,528 

4,733 



20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 





20 

100 

300 

600 

800 

1,000 

1,200 

1,400 

1,800 



20 

100 

500 

1,000 

3,400 



20 

60 

100 

150 

200 



20 

100 

200 

400 

900 



20 

100 

200 

400 

600 

1,200 



20 

100 

200 

400 

600 

1,000 

1,400 



400 

600 

1,700 



20 

100 

200 

300 

400 

500 

700 


ojoo 
36.56 
36.56 


" C. 
20. 10 




21.42 
21.39 




36.60 
36.33 
35.95 
35.35 
35.03 
35.07 


18.20 
17.70 
15.11 
11.11 




5.53 
4.70 


Feb. 26 


34.96 
36.62 
35.03 
35.03 
36.53 


3.79 
21.58 










Feb. 27 


21.75 




21 73 




36.53 
36.53 
35.93 
35.19 
35.03 
35.05 


19.88 
18.01 
14.67 




10.05 
5.35 
4.54 


Feb. 28 


35.01 
36.53 
36.49 


3.74 
21.55 




21.70 
21.70 




36.51 
36.47 
35.82 
35.21 
35.03 
35.01 
34.97 
34.99 
36.58 


21.38 
17.90 
14.07 
9.87 






Mar. 3 


4.37 

3.74 

22.83 




22.84 




36.56 
35.64 
35.03 
34.92 
36.06 
36.02 
36.08 
36.00 
35.66 
35.30 
36.11 
36.11 


22.82 

12.93 

5.20 

2.86 

20.78 




20.89 
20.59 
15.56 
13.39 
n.03 
23.35 
23.06 
20.34 






13.98 






10.36 


Mar. 14 


34.90 
35.97 
36.00 
36.06 
36.53 
36.17 
35.28 
34.92 
35.93 
35.93 
36.26 
36.68 
35.66 
35.03 
34.87 


7.00 
24.34 




24.60 


Mar. 18 


23.31 
15.93 
11.24 
5.03 

24.78 




24.72 
24.45 
22.34 
13.51 
9.10 
8.31 
4.36 


Mar. 19 


36.08 


23.61 




18 37 






13.45 




34.94 
36.17 






23.35 
23.30 




36.26 
36.67 
36.44 
36.26 
35.81 
35.53 


23.23 
21.82 
18.71 
16.63 
14.15 
12.17 



58 EXPLORATIONS, WESTEEN ATLANTIC, STEAMER BACHE, 1914, 
Table op Salinities and Temperatures; "Bache" Stations, 1914 — Continued. 



Date. 


Station. 


Lat. N. 


Long. W. 


Depth. 


SaUnity. 


Tempera- 
ture. 






o , 


o / 


Meters. 


ojoo 


° C. 


Mar. 20 


10203 


25 34 


79 42 



20 
100 


36.08 


24.03 




24.03 




""36." 26' 


23.25 










200 


36.53 


20.17 










300 


35.99 


15.95 










400 


35.84 


14.42 










800 


34.85 


6.16 




10204 


25 33 


80 03 




20 
100 
150 


36.17 
36.20 
36.17 
35.30 


21.76 
21.83 
21.07 
10.72 




10205 


27 05 


79 52 




20 

60 

100 

175 

250 


36.02 
36.08 
36.22 
36.04 
35.43 
34.85 


23.60 
22.88 
22.48 
19.19 
12.25 
6.90 


Mar. 21 


10206 


27 17 


79 40 



20 


36.09 
36.11 


23.75 




23.40 










100 


36.26 


23.40 










200 


36.55 


20.13 










300 


35.82 


14.71 










400 


35.10 


9.68 










500 
700 




8.53 




""'34.' 85' 


5.70 




10207 


27 32 


79 21 



20 
100 
200 
300 
400 
500 


36.17 
36.17 
36.20 
36.56 
36.38 
36.08 
35.79 


23.70 
23.60 
23.30 
19.93 
17.61 
15.78 
13.90 




10208 


27 46 


7S 46 



20 
100 
200 


36.42 
36.44 
36.51 
36.53 


22.80 
22.42 




ig.'gi 










300 


36.42 


18.78 










500 


36.18 


16.39 










700 


35.37 


10.88 










800 


35.03 


8.26 


Mar. 22. 


10209 


27 57 


78 15 



20 


36.44 
36.45 


22.23 




21.52 










100 


36.49 


' 20.65 










200 


36.49 


18.57 










400 


36.11 


16.11 










500 
700 


35.97 
35.26 






io.'os 










800 
900 




7.41 




"'"35.'6i' 


5.98 




10210 


27 59 


77 25 



20 
100 
200 
300 
450 
600 
800 
1,000 


36.42 
36.40 
36.51 
36.55 
36.49 
36.31 
36.00 


21.78 
21.80 
21.56 
20.80 
17.44 
17.06 




10.29 




'""35.'i6' 


6.04 




10211 


28 08 


76 48 



20 
100 


36.55 


,20.98 
21.02 




'"'36.' 55' 


20.85 










300 


36.42 


17.81 










500 


36.22 


16.29 










700 


35.73 


13.38 










850 
1,000 




8.57 




'"'35.' 67' 


6.64 


Mar. 23 


10212 


(^ 28 10 


76 18 



20 


36.60 
36.56 


20.75 




20.80 










100 


36.56 


20.50 










300 


36.26 


17.77 










500 


35.97 


14.62 










750 


35.10 


10.01 










1,000 


35.03 


5.62 










1,800 


35.01 


3.67 



EXPLOEATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 59 

Density on Profile Cape Florida-Gun Cay, 1914, Corrected for Pressure 
BY Ekman's (1910) Tables. 



Station. 


Depth. 


Densitj'o 
corrected 
for pres- 
sure. 


Station. 


Depth. 


Densityo 
corrected 
for pres- 
sure. 


10202 


Meters. 

100 
200 
300 
400 
500 
700 


24.74 
25.34 
26.65 
27.46 
28.26 
29.04 
30.03 


10203 


Meters. 


100 
200 
300 
400 
800 


100 
500 


24.47 




10204 


25.34 
26.83 
27.84 
28.61 
31.09 
25.13 






25.84 
27.74 



a At temperature in situ. 

Density off Chesapeake, "Bache" Stations, January, 1913, Pressure 
Correction from Ekman's (1910), Table 4 Only. 



Station. 


Depth. 


Density" 
corrected 
for pres- 
sure. 


Station. 


Depth. 


Density" 
corrected 
for pres- 
sure. 


10157 


Meters. 



18 



20 

36 



20 

100 

200 


23.65 
26.40 
25.92 
25.94 
26.23 
26.60 
26.69 
27.31 
28. 50 


10158 


Meters. 



20 

100 

300 

700 

1,100 

1,800 



20 

100 

200 

600 

1,000 


26.57 


10159 


10161 


26.63 
27.08 


10160 


28.39 
31.04 
32.99 




36.20 
25.58 






25.64 
26.10 
27.11 
29.60 
31.90 



a At temperature in situ. 

"Roosevelt" Stations Off Virginia Capes, January and February, 1916. 



Station. 


Bearings. 


Date. 


Depth. 


Station. 


Bearings. 


Date. 


Depth. 


Lat. N. 


Long. W. 


Lat. N. 


Long. W. 


D8442 

D8443 

D8444 

D8445 

D8446 

D8447 

D8448 

D8449 


o / 

36 55f 
36 57i 
36 57| 
36 58 

36 56i 

37 21i 
37 211 
37 22 


75 57 
75 36 
75 llj 
74 41i 
74 36J 
74 27-i 
74 32J 
74 40| 


Jan. 27 
Jan. 27 
Jan. 27 
Jan. 27 
Jan. 28 
Jan. 28 
Jan. 28 
Jan. 28 


Meters. 
19 
19 
38 
131 
479 
415 
94- 
59 


D8450 

D84510 

D8452 

D8453 

D8454 

D8455 

D8456 

D8457 


37 22i 

37 22 
36 35^ 
36 36J 
36 36| 
36 37 
36 37 

38 21 


75 14i 
75 24 
75 44 
75 l&l 
74 58 
74 421 
74 40J 
73 38 


Jan. 28 
Jan. 28 
Jan. 31 
Jan. 31 
Jan. 31 
Jan. 31 
Jan. 31 
Feb. 1 


Meters. 
28 
13 
20 
26 
38 
60 
340 
125 



o Bell buoy W. i N., li miles. 



60 EXPLORATIONS^ WESTERN ATLANTIC, STEAMER BACHE, 1914. 

Table of Temperatures, Salinities, and Densities at "Roosevelt" Stations, 
January and February, 1916. 

[Density is at the temperature in situ, corrected for pressure by Ekman's (1910) tables.^ 



Station. 



Depth. 


Tem- 
per- 
ature. 


Salin- 
ity. 


Density. 


Meters. 


°C. 


o/oo 







6.11 


29.34 


23.12 


11 


6.67 


30.93 


24.39 


17 


6.67 


32.34 


25.52 





7.22 


30.79 


24.13 


9 


6.95 


33.01 


25.92 


18 


7.11 


33.35 


26.23 





8 33 






18 


7.89 


33.64 


26.32 


33 


8.00 


33.62 


26.36 





11.39 


34.63 


26.43 


27.5 


11.11 


34.58 


26.63 


55 


10.83 


34.56 


26.68 


131 


12.33 


35.28 


27.46 





12.22 


34.49 


26.20 


55 


11.83 


34.96 


26.81 


110 


12.78 


35.21 


27.06 


183 


11.67 


35.30 


27.73 


238 


10.17 


35.25 


28.26 


478 


5.89 


35.05 


29.84 





10 


34.38 


26.50 


55 


10.56 


34.76 


27.03 


110 


12.56 


35.19 


27.29 


183 


11.67 


35.35 


27.54 


238 


10.56 


35.21 


28.24 


414 


7.78 


34.94 


29.23 





10.28 


34.38 


26.50 


27.5 


10.56 


34.42 


26.59 


55 


10.56 


34.58 


26.82 


92 


12.22 


35.12 


27.14 



Station. 



Depth. 



Tem- 
per- 
ature. 



Salin- 
ity. 



Den- 

sity. 



D8442. 
D8443. 
D8444. 
D8445. 

D8446. 



D8447. 



D8448. 



D8449. 

D8450. 

D8451. 
D8452. 
D8453. 

D8454, 

D8455 

D8456, 



D8457. 



Meters. 



27.5 

57.5 



11 

16 



12 



19 



11 

22 



18 

37 



18 

55 



55 

110 

183 

238 

293 

337 



20 

55 

124 



"C. 

8.05 
9.33 
10.67 
6.95 
7.22 
7.00 
5.83 
6.22 
7.33 
7.89 
8.33 
8.78 
8.56 
8.89 
9.56 
10 
9.33 
11.11 
1L39 
12.22 
12.22 
12.67 
12.50 
11.89 
10.56 
10.11 
12.50 
10.83 
11.11 
11.11 



O/flO 

33.53 
33.86 
34.69 
33.35 
33.37 
33.37 
32.57 
32.52 
30.25 
33.17 
33.64 
33.68 
33.66 
33.96 
34.02 
34.23 
34.02 
34.38 
34.61 
34.72 
34.97 
35.05 
35.32 
35.26 
35.30 
34.97 
34.29 
35.01 



26.14 
26.39 
26.93 
26.14 
26.25 
26.29 
25.67 
25.67 
23.70 
25.96 
26.18 
26.22 
26.26 
26.34 
26.45 
26.52 
26.32 
26.42 
26.66 
26.39 
26.83 
27.07 
27.63 
27.91 
28.53 
28.53 
25.92 
26.91 



35.16 



27.50 



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EXPLORATIONS, WESTERN ATLANTIC, STEAMER BACHE, 1914. 61 

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62 EXPLORATIONS^ WESTERN ATLANTIC^ STEAMER BACHE^ 1914. 
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o 



BACHE," JANUARY-MARCH, 1914, W 




LOCATION OF STATrONS. 



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